diff --git a/src/main/java/com/widen/tabitha/RowReaderFactory.java b/src/main/java/com/widen/tabitha/RowReaderFactory.java
index 5ea4d3e..b40da5b 100644
--- a/src/main/java/com/widen/tabitha/RowReaderFactory.java
+++ b/src/main/java/com/widen/tabitha/RowReaderFactory.java
@@ -1,13 +1,12 @@
 package com.widen.tabitha;
 
-import com.widen.tabitha.formats.delimited.DelimitedRowReader;
 import com.widen.tabitha.formats.delimited.DelimitedFormat;
-import com.widen.tabitha.formats.excel.WorkbookRowReader;
+import com.widen.tabitha.formats.delimited.DelimitedRowReader;
 import com.widen.tabitha.formats.excel.XLSRowReader;
 import com.widen.tabitha.formats.excel.XLSXRowReader;
-import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
 import org.apache.tika.Tika;
 
+import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -69,6 +68,9 @@ public static Optional<RowReader> open(InputStream inputStream) throws IOExcepti
      * @return A row reader if the stream is in a supported format.
      */
     public static Optional<RowReader> open(InputStream inputStream, String filename) throws IOException {
+        // If our input stream supports marks, Tika will rewind the stream back to the start for us after detecting the
+        // format, so ensure our input stream supports it.
+        inputStream = createRewindableInputStream(inputStream);
         String mimeType = tika.detect(inputStream, filename);
 
         switch (mimeType) {
@@ -90,6 +92,10 @@ public static Optional<RowReader> open(InputStream inputStream, String filename)
         return Optional.empty();
     }
 
+    private static InputStream createRewindableInputStream(InputStream inputStream) {
+        return inputStream.markSupported() ? inputStream : new BufferedInputStream(inputStream);
+    }
+
     // Apache Tika instance for detecting MIME types.
     private static final Tika tika = new Tika();
 }